1. Field of the Invention
The present invention concerns a shockwave system for in vivo treatment of calculi in patients.
2. Description of the Prior Art
Shockwave systems are used in medicine in order to treat people or animals as patients with ultrasonic shockwaves. The purpose of such a treatment is usually to shatter (disintegrate) a calculus located in the patient (such as, for example, a kidney or bladder stone) with the ultrasonic shockwaves focused on the calculus. Although the shockwave treatment of a patient is benign to the patient due to its non-invasive character, it is nevertheless not free of complications.
A known problem is the triggering of heart rhythm disruptions by the ultrasonic waves. The risk of such extrasystoles is reduced by temporally synchronizing the shockwave system with the ECG, thus the heart rhythm of the treated patient, to the greatest extent possible. Further problems exist when ultrasonic shockwaves impact the patient tissue surrounding the calculus. Here the danger exists of tissue injury TO the patient. The treatment of kidney stones, for example, can easily lead to damaging the kidney parenchyma, the kidney tissue that is significantly perfused with blood. The higher the blood pressure of the patient during the shockwave treatment, the higher the probability of bleeding or initiation of tears in the kidney tissue, thus a kidney hematoma.
In the general case, high blood pressure in a patient therefore represents a contraindication for a shockwave treatment. For example, kidney stone lithotripsy is no longer undertaken for a patient having a systolic blood pressure of over 160 mmHg. Today, the blood pressure of the patient is additionally normally measured or monitored during a shockwave treatment, for example with a commercially available patient monitor for monitoring blood pressure, ECG and oxygen content of the blood. It is hereby incumbent upon the doctor, for example the doctor conducting the shockwave treatment, to always observe the patient monitor and thus monitor the blood pressure of the patient. Patient monitors also exist on which a threshold for the blood pressure can be set. If the blood pressure reaches the threshold, an optical or acoustic alarm signal is triggered.
Since the doctor is primarily occupied with the shockwave treatment, for example the stone tracking and the monitoring of the degree of destruction of the calculus, the blood pressure monitoring represents an additional burden for him or her. For the patient the risk additionally exists that the doctor (due to inattention, read errors or the like) may overlook critical blood pressure values of the patient, and the patient is thus exposed to the risks of complications. The programming of the blood pressure threshold at the patient monitor can be forgotten or the warning signal can be unnoticed.